For some vehicles, it may be desirable to use an engine and a transmission that have incompatible torque and speed characteristics. For example, the engine has a high-torque, low speed characteristic and the transmission has a low-torque, high speed characteristic. Unfortunately, if the engine and transmission are directly connected, the differences in characteristics result in unsatisfactory operation of the vehicle. If the engine and transmission are connected through a torque converter, the operation is still unsatisfactory. Thus, there is a long-felt need for a means of interfacing engines and transmissions with incompatible torque and speed characteristics.